Lifetime enhancement of quasibound states in graphene quantum dots via circularly polarized light

Abstract

Permanent localization of electrons inside a graphene quantum dot (GQD) is known to be forbidden, as a manifestation of Klein tunneling. However, an electron which scatters on a GQD may be transiently trapped inside and one known practice is the usage of magnetic field. These electronic states discussed here, called quasibound states, are scattering resonances typically characterized by a finite lifetime (trapping time). In this paper, we present a theoretical perspective concerning the opportunity to enhance the lifetime of quasibound states excited in a GQD placed in a uniform magnetic field, using circularly polarized light. Generally speaking, electron trapping inside GQDs is achievable for certain well-defined conditions, for instance, magnetic field intensity. We report here that the trapping time of an electron inside a GQD may be successfully enhanced by adjusting the light intensity while keeping the magnetic field constant.